I'm just about to bottle that exact beer.
Yep, halve the whole recipe.
And don't put your nose over the sugar while its cooking and take a big smell. There will be some ammonia offgassing, and it won't smell (or feel) very nice.
Use a good thermometer, and have a small bit of foil ready so you can confirm the colour. It will look really dark in the pot, but you can put a dab on the foil and check the colour with the colours on this page.
Have fun, it will seem like its going really slow for a while, but things start going pretty quickly towards the end and it can get kind of exciting. Don't worry, if you mess it up you are only out a few pennies and you can start over